Ever had her lipase levels checked for pancreatitis? I have a dog with chronic pancreatitis and her symptoms are almost identical to what you describe.

I'd wait til she's eating and feeling better to do her vaccinations...well, personally, I wouldn't do them at all, but that's a whole other issue. My vet wouldn't vaccinate an already ill dog in any case.

Good luck. I hope you find an answer and Chloe feels better soon.